This invention relates to molded plastic articles, and, more particularly, to a method of reinforcing molded plastic articles.
A wide variety of articles are molded from plastic, and one particularly popular plastic is polyethylene. Polyethylene is inexpensive yet has many desirable physical characteristics such as high impact strength under a wide range of temperatures, good abrasion, good weatherability, and ease of cleaning. These and other properties can be improved or optimized by using various additives as is well known in the art.
However, one of the problems with polyethylene is that it is difficult to join other materials to polyethylene. The smooth surface of polyethylene does not provide good adhesive bonding, and any fasteners which are inserted through the polyethylene would cause stress concentrations and would be a potential area for leaks. Also, polyethylene has a higher thermal expansion than most other materials, and differing rates of thermal expansion between polyethylene and another material attached to it could affect the attachment.
Another difficulty with polyethylene is that it is not rigid and cannot be used for structural parts with out reinforcement. However, if a reinforcing member is attached to the polyethylene, the different rates of thermal expansion could cause problems.